Quillworts: Nuttall’s Quillwort (Isoetes nuttallii) & Flowering Quillwort (Lilaea scilloides)

As we welcome the rainy season in California, as the hills awaken from their drought-induced dormancy, I thought I’d introduce two taxa that will soon appear. Those of you who are accustomed to reading in this column descriptions of the more attractive members of our native flora might be horribly disappointed with the subjects of this issue, as these two plants are practically invisible and can only be appreciated by the geekiest of belly crawling botanists. I give you – the quillworts!

Quillworts are tiny, sedge – or grass-like denizens of aquatic or marshy locales. Other than morphology and common names, these two unrelated species have little in common. While both are vascular plants, they differ dramatically in that Isoetes reproduces by spores, while Lilaea is an angiosperm, producing true flowers and seeds. Both form tufts of narrow, quill-like leaves usually no more than four inches tall. Both can easily be overlooked or mistaken for the likes of toad rush (Juncus bufonius), low bulrush (Isolepis [Scirpus] cernuus), spikerush (Eleocharis), young grasses, or other monocots. You’re forgiven if you stop reading now.

Nuttall’s quillwort (Isoetes nuttallii) belongs to the Lycopodiopsida, a class of plants that diverged in the Early Devonian Period, nearly 395 million years ago, about 150 million years before the evolution of flowering plants. This was the same period that witnessed the diversification of the fishes and the origin of amphibians. Nuttall’s quillwort belongs to the Isoetales, an order that first made its appearance in the Upper Devonian/ Early Carboniferous (about 345 million years ago). There are two extant genera in this order, Isoetes and Stylites. Both are small, herbaceous plants restricted to marshy or aquatic environments. Stylites is found only in bogs bordering a lake in the Andes Mountains of Peru. Paleobotanists mostly agree that the members of Isoetales represent the last living remnants of the group that gave rise to the club-mosses (Lycopodium) and spike mosses (Selaginella).

Nuttall’s quillwort is a member of the family Isoetaceae, the quillwort family. The genus Isoetes consists of about 150 species with a nearly worldwide distribution, albeit restricted mostly to cool climates. Some 24 taxa in the quillwort family are recorded in the Flora of North America, with six native species found in California. The leaves of Nuttall’s quillwort are hollow and quill-like, arising from a central perennial corm. It is drought-deciduous, losing its leaves in the summer and surviving the dry season underground. Nuttall’s quillwort inhabits many plant communities, including chaparral and lodgepole pine forest, although it is restricted to seasonally wet sites near vernal pools or temporary streams within those plant communities. It occurs from San Diego northward along the coast, Great Central Valley, and the Sierra foothills through Oregon and Washington, up to 9,000 feet in elevation.

In San Francisco, Nuttall’s quillwort was collected in 1938 from a springy slope above the Presidio Golf Course (Howell, et al. A Flora of San Francisco, California, 1958). According to Michael Chasse of the National Park Service and Mark Frey of the Presidio Trust, it can still be found at the Presidio in the open field along Washington Boulevard across from Immigrant Point, as well as in the remnant prairie adjacent to the Log Cabin. It is not known from any other San Francisco location or from San Bruno Mountain.

Although morphologically similar, at least to those who are not lying down with their noses in the dirt, flowering quillwort (Lilaea scilloides) is a true flowering plant which produces seeds, not spores. As a member of the order Potamogetonales, it is related to the pondweeds (Potamogeton, Stuckenia), ditch-grass (Ruppia), arrow-grass (Triglochin), surfgrass (Phyllospadix), and eelgrass (Zostera).

Flowering quillwort is a monocot belonging to the arrow-grass family (Juncaginaceae [formerly Lilaeaceae]). This family consists of a single species in a single genus, with a range that extends along the western edges of North and South America from southern Chile and Argentina to British Columbia. In the United States, flowering quillwort occurs in California, Oregon, Nevada, Washington, Idaho, and Montana. In California, it is very common in wet soils near ponds, lakes, and slow streams of coastal and interior valleys. It occurs up to about 5,000 feet in elevation and can be found in most of the state’s cismontane counties.

In San Francisco, flowering quillwort was collected in the swamps of the Presidio and near Lake Merced (Howell, et al. 1958). Michael Chasse reports that it still can be found at the Presidio on a seasonally flooded site adjacent to the serpentine outcrop at Inspiration Point. Although it has also been recorded at McLaren Park, that population is likely to have been extirpated.

Neither Nuttall’s quillwort nor flowering quillwort is regarded as a rare or threatened species by the California Department of Fish and Game (CDFG) or the California Native Plant Society (CNPS). Flowering quillwort is considered a species of local significance by the Yerba Buena Chapter of CNPS due to its restricted occurrence in the county. Nuttall’s quillwort is not currently considered a species of local significance, although its restricted occurrence here and the limited availability of suitable habitat in the chapter area might be cause for reconsideration.

Populations of both “quillworts” at the Presidio represent an unusual and rare resource, and, I’m happy to be able to report, they are being monitored and managed. Kirra Swenerton of the Golden Gate National Parks Conservancy is even experimenting with techniques for propagation of Nuttall’s quillwort in hopes of expanding its population size. If you’d like to learn more about restoration programs at the Presidio, or to volunteer, contact the Community Programs Manager Adam Sharon at the Presidio native plant nursery at 415-561-4826. Maybe, if you’re really friendly, they’ll show you the quillworts in their natural setting. Happy winter. Let it rain.